Originally Posted by
fat2fit
I heard they just spit the dirt/water back into the tires and into the brakes and could cause more trouble than they're worth, and you still get dirty with them on.
Depends on the fender. Unfortunately, a lot of bikes are designed to not take fenders, and a lot of fender designs are more concerned about fitting on such bikes than being good fenders. And a lot of fenders - perhaps even most fenders - are also just really poorly designed, seemingly designed by people unaware of where water travels after getting picked up by the tire.
A well-designed fender on a bike designed to accommodate fenders can provide good protection from filth, and if it's mounted cleanly and is the right color, it can look great as well.
The top of the front fender should extend far out in front so that your cockpit and torso/face are protected against spray from the top of the front tire. The bottom of the front fender should be low enough to protect your drivetrain and feet. The back of the rear fender should, ideally, extend low enough to protect the person behind you. The fender should be wider than the tire, and on its sides, it should have channeled edges that route water to the front and back of the fender so that blocked water doesn't simply drip onto your bike.
Originally Posted by
fat2fit
I found these on Trek's website. They are on sale, full fenders for both front & rear. I'm assuming these will fit my bike? I personally hated the look of the fenders at first but I kinda like them, maybe it's because I'm getting older lol
https://www.trekbikes.com/ca/en_CA/e...olorCode=black
No, avoid those. For several reasons.
Firstly, the only option in the page you linked is the fender designed for 18-25mm tires, which is waaaaaaay too narrow for the tires on your Dual Sport. You'll get loads of side spray even if you position the fender dangerously low over the tire.
Secondly, here's a slightly-wider version of that same fender, mounted on a former bike of mine:
Both fenders are too short. The rear fender didn't protect the person behind me at all, water sprayed into my face from the top of the front tire, and most importantly for my own solo riding, the front fender's mudflap was far too high up to protect my feet from the spray off the front tire. It's better than no fender because it protected me from *most* of the spray, but the experience is nothing compared with a fender that blocks nearly everything.
Unfortunately, sensibly-designed fenders don't seem to exist at a low price point. The cheapest fenders that do a truly-proper job are probably Velo Orange fenders at ~$80, and those are lightweight classic aluminum fenders, which require a careful install if you want them to last a long time. They work very well though, particularly once you add a front mudflap:
Some sizes of some cheaper fenders do okay. For instance, the road-width Planet Bike Cascadia fenders on my old Fuji are *reasonably* effective, although some sizes of some variants don't extend as far at the mudflaps. The super-fat 26er Bontrager NCS fenders on my gravel bike extend considerably lower in front than the skinnier NCS fenders in the above photo, and do a surprisingly good job with foot and drivetrain protection, although they still don't help the person behind me.